You might be pleased with your new wireless equipment that can transmit signals as far as a few houses down the street, but Ermanno Pietrosemoli (president of the Escuela Latinoamerica de Redes, which translates as networking school of Latin America) has managed to establish a WiFi link between two computers placed 382 km apart – that’s about 238 miles. Using this connection, Pietrosemoli managed to achieve transfer rates of about 3 megabits per second, which is quite impressive considering the distance involved. This figure represents a new record for a WiFi connection, and was achieved using a combination of technology from Intel and some “off-the-shelf” parts, set up to transfer data to a specific point rather than in all directions. The previous record was held by a group of Swedish scientists that managed to create a WiFi connection between a hot air balloon and an Earth-bound station 310 km apart, so this exceeds that by almost 25%.

Hmmm, 382km... shouldn't the curvature of the earth kick in at a distance like that?
Sadly they don't seem to mention what the local conditions were, nor whether they used 802.11b/g (2,4 GHz) or 802.11a (5 GHz)

Can't to something like that in my country. Maximum for WiFi is 100mW, so a no-go for distances like that.